A work machine may include a transmission coupled to a power source, such as an internal combustion engine or an electric motor, to provide more flexible use of the power output by the power source. For example, the transmission may provide a number of gear ratios that enable the work machine to travel at a relatively wide range of speeds or conditions that might be impractical without a transmission. In some work machine applications, the transmission may provide a directional shifting capability, also known as “shuttle shifting,” that permits the operator to command a machine direction reversal (e.g., by shifting a lever). The transmission may respond to this command by causing the work machine to slow down and change direction, and may alleviate the need for the operator to press a brake and stop the machine, move the transmission shifter from forward to reverse or vice versa, and press the accelerator.
To perform a directional shift, energy is required to decelerate the machine in a current travel direction, and then accelerate the machine in the opposite direction. Similarly, energy is required to upshift, downshift, or otherwise change the velocity of the machine. Much of the energy required for the change in the machine's velocity is provided by the clutches within the transmission. The energy requirement may cause heat to be generated at the transmission clutches during the directional shift, and can result in clutch failure when the clutch temperature repeatedly exceeds the material durability limits of the clutch components.
One attempt to limit clutch temperatures within a transmission during high speed shifts is disclosed in U.S. Pat. No. 9,689,490 that issued to Patenaude et al. on Jun. 27, 2017 (“the '490 patent”). In particular, the '490 patent discloses a machine velocity change shift strategy that determines acceptable transmission output shaft velocity changes that require less energy to execute the directional shift and reverse the direction of travel of a work machine so that the oil temperature within the transmission will not reach levels that compromise the clutch glue or otherwise adversely affect the components of the transmission. The machine velocity change shift strategy disclosed in the '490 patent factors in changes in the grade of the work surface, the mass of the work machine, and the temperature of the transmission oil to adjust the energy required for the directional shift and the acceptable transmission output shaft velocity change that can vary with these parameters.
However, there may be additional factors or parameters that may impact a machine velocity shift strategy, such as whether controlled throttle shifting, which may regulate an engine speed during gear shift, is enabled or disabled for the work machine. The transmission control system of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.